A bulge in the aorta, known as aortic aneurysm, can result from factors that weaken the wall of this major artery. Although aortic aneurysms often present no symptoms, rupture (bursting) sets off a life-threatening emergency. The exact causes of aortic aneurysms have yet to be identified, but some contributing factors are known. Some of the known risk factors can be avoided or controlled.
Tobacco Use
Smoking or using other forms of tobacco contributes significantly to the development of aortic aneurysms, according to the Merck Manual. Smoking directly damages the arteries, weakening their walls and increasing the risk of developing an aneurysm, and it also increases blood pressure and contributes to hardening of the arteries (atherosclerosis), factors that increase the risk of an aortic aneurysm growing and bursting.
Cardiovascular Disease
As the major supply stream for blood to the body, the aorta–normally about the diameter of a garden hose–is designed to withstand high pressure. However, as blood pressure increases outside of the normal range, segments of the aorta can buckle under the added strain. Cardiovascular conditions such as poorly controlled high blood pressure (hypertension) and atherosclerosis (hardening and narrowing of the arteries) place an added burden on the aorta; over time, these conditions can cause an aneurysm, according to the Mayo Clinic.
Other Diseases
Rarely, an infection or inflammation of the aorta weakens it, causing an aneurysm. General inflammation of the blood vessels, called vaculitis, can cause an aortic aneurysm. Untreated syphilis also can lead to an aortic aneurysm, according to the National Heart, Lung and Blood Institute (NHLBI).
Genetics
Aortic aneurysms can run in the family, suggesting a genetic component. The Merck Manual reports that 15 to 20 percent of patients with aortic aneurysm have a family history of the condition. People with a family history of aortic aneurysm have a higher risk of developing them, tend to develop them at a younger age and have a higher risk that the aneurysm will burst. However, the causative genetic factors are unknown.
Some genetic conditions such as Marfan syndrome and Ehlers-Danlos syndrome weaken the body’s connective tissues, including the walls of the aorta, increasing the risk for an aortic aneurysm in the chest (thoracic aortic aneurysm), according to the NHLBI.
Other Risk Factors
The Mayo Clinic explains that aortic aneurysms occur most often in people age 60 or older. Aortic aneurysms develop more frequently in Caucasians as compared to other racial backgrounds. Men are five to 10 times more likely to have an aortic aneurysm than women, but women who develop an aortic aneurysm run a greater risk of it bursting than the typical male patient, according to the Mayo Clinic.
Blunt trauma to the chest (for example, from a car accident or a fall from an extreme height) can cause a thoracic aortic aneurysm.
About this Author
In 20 years as a biologist, Susan T. McClure has contributed articles to scientific journals such as “Nature Genetics” and “American Journal of Physiology.” She earned her Ph.D. from the University of Maryland. She enjoys educating people about science and the challenge of making complex information accessible.
